Specifications

36
Touch Activation Modes
Activation mode refers to the behavior
of the target when it is touched. Slides,
switches and buttons are typical variations of
touch targets. A typical button target has
three states: unarmed, armed, and activated.
The simplest activation mode is the
activation of the target whenever a finger is
over the target. The target proceeds directly
from the unarmed state to the activated state,
in much the same manner as a mouse pointer
might activate by simply pointing to an area
without clicking a button. This method of
activation is the least desirable because it is a
one-step process that lacks a means of
canceling the activation of a target. This
makes unintended activation likely.
A variation of this method is to activate
the target when the finger is removed from
the screen over the target. This activation
mode is only slightly better, since it also
means that there is no way of canceling the
activation, and the results can be inadvertent
activation.
The most frequently used activation
mode is to cause the target to go to the armed
state whenever the finger is over the target.
If the finger is over the target when it is
withdrawn from the screen, the target is
activated. If the finger moves away from the
target before the finger is withdrawn from
the screen, the target is not activated. This
allows the user to cancel the selection.
Touch Feedback
Feedback is an integral part of most well
designed activation modes. The user must
receive immediate feedback to know for
certain when a target has been armed and/or
activated. Highlighting, changing color, or
depressing a chiseled button are all good
visual feedback techniques for indicating
that a touch target is armed or activated.
Never let the screen go blank, even if
dummy screens must be designed to fill up
the display screen. To the inexperienced
user, a dark screen is a sure sign that the
system has failed.
Audio feedback is an appealing
complement to visual feedback, with various
tones or sounds being used to indicate the
target activation state. This effect can be
especially impressive on multimedia
computers.